U.S. patent application number 11/683235 was filed with the patent office on 2007-08-02 for molded stone architectural product having a foam core.
Invention is credited to Dave Nicolson, Marc Stephenson.
Application Number | 20070175139 11/683235 |
Document ID | / |
Family ID | 38231404 |
Filed Date | 2007-08-02 |
United States Patent
Application |
20070175139 |
Kind Code |
A1 |
Nicolson; Dave ; et
al. |
August 2, 2007 |
MOLDED STONE ARCHITECTURAL PRODUCT HAVING A FOAM CORE
Abstract
An architectural cast stone product for use in building
construction has a unitary shell made of a molded cementitious
material that partially surrounds and is affixed to a foam core.
The architectural cast stone product has a mounting surface
including an exposed surface of the foam core and an exposed
surface of the shell. The architectural cast stone product is made
by obtaining a front pattern having a desired surface configuration
for the architectural cast stone product, obtaining a foam core,
affixing the foam core to a backer, affixing the front pattern to
the backer that together form a mold, pouring a cementitious
material into the mold and into contact with the foam core, at
least partially curing the cementitious material to form the
architectural cast stone product, and removing the front pattern
and backer from the architectural cast stone product. The
architectural cast stone product may optionally be surface
finished, such as by sanding or polishing, to yield a desired
surface finish.
Inventors: |
Nicolson; Dave; (Orem,
UT) ; Stephenson; Marc; (Orem, UT) |
Correspondence
Address: |
WORKMAN NYDEGGER;(F/K/A WORKMAN NYDEGGER & SEELEY)
60 EAST SOUTH TEMPLE
1000 EAGLE GATE TOWER
SALT LAKE CITY
UT
84111
US
|
Family ID: |
38231404 |
Appl. No.: |
11/683235 |
Filed: |
March 7, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10900969 |
Jul 28, 2004 |
|
|
|
11683235 |
Mar 7, 2007 |
|
|
|
60490626 |
Jul 28, 2003 |
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Current U.S.
Class: |
52/309.17 |
Current CPC
Class: |
B28B 7/348 20130101;
B28B 7/346 20130101; B28B 19/0046 20130101 |
Class at
Publication: |
052/309.17 |
International
Class: |
E04C 1/00 20060101
E04C001/00 |
Claims
1. An architectural cast stone product, comprising: a lightweight
foam core; a single continuous cementitious shell comprised of a
molded cementitious material and that partially surrounds the foam
core, wherein the cementitious shell is affixed to the foam core;
and a mounting surface comprised of an exposed surface of the foam
core and an end surface of the cementitious shell.
2. An architectural cast stone product as in claim 1, wherein the
exposed surface of the foam core is substantially flush with the
end surface of the cementitious shell.
3. An architectural cast stone product as in claim 1, wherein the
foam core includes a recess adjacent to the exposed and wherein the
cementitious shell comprises a wraparound extension that extends
laterally along the mounting surface into the recess of the foam
core.
4. An architectural cast stone product as in claim 3, wherein the
wraparound extension extends parallel to the exposed surface of the
foam core and nonparallel to an adjoining surface of the
cementitious shell.
5. An architectural cast stone product as in claim 1, wherein the
cementitious shell comprises a projection which extends into the
foam core so as to at least partially assist in affixing the
cementitious shell to the foam core.
6. An architectural cast stone product as in claim 1, wherein the
cementitious shell includes two transversely oriented sections that
meet so as to have the appearance of a miter joint.
7. An architectural cast stone product as in claim 1, wherein the
foam core is comprised of expanded polystyrene.
8. An architectural cast stone product as in claim 1, wherein the
foam core has a density less than about 2.0 lbs/ft.sup.3.
9. An architectural cast stone product as in claim 1, wherein the
cementitious shell has a thickness greater than about 1/4 inch.
10. An architectural cast stone product as in claim 1, wherein the
cementitious shell has a thickness in a range from about 1/4 inch
to about 1 inch.
11. An architectural cast stone product as in claim 1, further
comprising a front pattern surrounding an exposed outer surface
portion of the cementitious shell.
12. An architectural cast stone product as in claim 11, wherein the
front pattern has a non-planar surface configuration with
three-dimensional features corresponding to a shape of the exposed
outer surface of the architectural cast stone product.
13. An architectural cast stone product as in claim 12, wherein the
front pattern is comprised of expanded polystyrene foam.
14. An architectural cast stone product as in claim 1, the
cementitious shell having a surface that is non-planar with
three-dimensional features.
15. An architectural cast stone product as in claim 1, wherein the
cementitious shell has a polished surface finish.
16. An architectural cast stone product, comprising: a lightweight
foam core; a single continuous cementitious shell comprised of a
molded cementitious material and that partially surrounds the foam
core, wherein the cementitious shell is affixed to the foam core
and has an outer surface configuration that is non-planar with
three-dimensional features; and a mounting surface comprised of an
exposed surface of the foam core and an end surface of the
cementitious shell.
17. An architectural cast stone product as in claim 16, wherein the
exposed surface of the foam core is substantially flush with the
end surface of the cementitious shell.
18. An architectural cast stone product as in claim 16, wherein the
foam core includes a recess adjacent to the exposed and wherein the
cementitious shell comprises a wraparound extension that extends
laterally along the mounting surface into the recess of the foam
core.
19. An architectural cast stone product as in claim 1, wherein the
cementitious shell has a polished surface finish.
20. An architectural cast stone product, comprising: a lightweight
foam core; a single continuous cementitious shell comprised of a
molded cementitious material and that partially surrounds the foam
core, wherein the cementitious shell is affixed to the foam core;
and a mounting surface comprised of an exposed surface of the foam
core and an end surface of the cementitious shell, the end surface
of the cementitious shell including a wraparound portion that
extends laterally into a recessed portion of the foam backer.
21. An architectural cast stone product as in claim 20, wherein the
exposed surface of the foam core is substantially flush with the
end surface of the cementitious shell.
22. An architectural cast stone product as in claim 1, wherein the
cementitious shell has a polished surface finish.
23. An architectural cast stone product manufactured according to a
method comprising: obtaining a front pattern having a desired
surface configuration for the architectural cast stone product;
obtaining a foam core; affixing the foam core to a backer; affixing
the front pattern to the backer, wherein the front pattern and the
backer together form a mold having a mold cavity between the foam
core, front pattern and backer; introducing a cementitious material
into the mold cavity and into contact with the foam core; partially
curing the cementitious material to form the architectural cast
stone product comprised of a cementitious shell at least partially
surrounding the foam core; removing the front pattern and backer
from the architectural cast stone product while the cementitious
material is only partially cured and before it is fully cured in a
manner so that the foam core and cementitious shell remain attached
together as the architectural cast stone product; and polishing a
surface of the cementitious material to yield an architectural cast
stone product comprised of the cementitious shell affixed to the
foam core and having a polished surface finish.
24. An architectural cast stone product as in claim 23, wherein the
polished surface finish of the architectural cast stone product is
produced by polishing the cementitious material while only
partially cured and before being fully cured.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a division of U.S. application Ser. No.
10/900,969, filed Jul. 28, 2004, which claims the benefit of U.S.
Provisional Application Ser. No. 60/490,626, filed Jul. 28,
2003.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to molded stone architectural
products having a foam core. The present invention further relates
to a slurry casting method for the manufacture of foam core
architectural stone products.
[0003] The use of natural cut and carved stone is often too
expensive to be used in most homes and buildings. Natural stone is
also heavy and subject to seismic limitations. Over the years,
various products and construction methods have been developed to
simulate cut and carved stone on home and building exteriors. For
example, many commercially available cementitious products may be
used to prepare three-dimensional shapes, which when cured, may
serve as window sills, crown moldings, window surrounds, moldings
around doors wall caps, keystones, columns, column caps and bases,
etc. With limitations similar to natural stone, architectural stone
products may be produced by casting cementitious material in a mold
to produce cast solid architectural stone products. Others cover
foam shapes with a thin layer of cementitious material, either at a
job site or at a shop. Each of these methods has limitations that
have created a need in the art. Cast solid architectural stone
products are heavy and expensive because of the amount of
cementitious material required to fabricate the product. The method
of coating a three-dimensional shaped substrate is wasteful and
often the product is of poor quality. Material is often wasted
because too much cementitious slurry is made and much material
falls to the ground during the coating process. Poor or uneven
quality results from the difficulty in applying a uniform coating
on the shaped substrate. In addition, this method is also expensive
because of the labor skill and time required in applying the
coating.
[0004] Accordingly, a need exists for molded stone architectural
products that are efficiently manufactured at low cost and have a
high quality three-dimensional shape and surface finish. There is a
further need for molded stone architectural products that
efficiently use materials, are inexpensive to manufacture, are
relatively lightweight, and are uniform in appearance. There is
still a further need for molded stone architectural products that
do not require fabrication at the job site.
BRIEF SUMMARY OF THE PREFFERED EMBODIMENTS
[0005] The present invention has been developed in response to the
present state of the art, and in particular, in response to the
problems and needs in the art that have not yet been fully solved
by currently available architectural stone products. The present
invention relates to a method of preparing a mold which is used to
manufacture architectural cast stone products containing a foam
core. As used herein, an architectural cast stone product is a
three dimensional decorative and/or functional structure that is
intended to have a stone-like appearance for exterior or interior
applications. Examples of architectural cast stone products include
but are not limited to columns, caps, bases, balustrades, barrel
vaulting, window sills, crown molding, wall caps, keystones,
fireplace mantles, column caps and bases, moldings around doors,
wall caps, trim stones, quoins, and door and window surrounds.
[0006] The architectural cast stone product of the invention may
include a foam core and a unitary shell made of a molded
cementitious material that partially surrounds the foam core. The
shell is formed of a cementitious material that is cast in a mold
around the foam core. During the casting process, a slurry of
cementitious material partially surrounds the foam core and fills
the crevices, cavities, and unevenness in the surface of the foam
core to affix the shell to the core as the shell cures.
Cementitious material is material having the properties of cement.
The cementitious material may include a wide variety of aggregates
including, but not limited to, stone fragments, glass fiber, glass
particles, sand, polymers, and other materials.
[0007] The architectural cast stone product includes a mounting
surface that includes an exposed surface of the foam core and an
exposed surface of the shell. The mounting surface is a surface
that may be hidden from view once it is attached to or installed on
a building structure. The shell of the architectural cast stone
product includes a wraparound extension that follows the foam core
from a first surface at least partially onto the mounting surface.
This wraparound extension may be the exposed surface of the shell
on the mounting surface. The wraparound extensions provide the
appearance that the architectural cast stone product is solid
stone. The exposed surface of the foam core limits the size of the
shell and thus limits the total weight of the architectural cast
stone product. In forming the mounting surface, the wraparound
extension may extend parallel to an adjoining surface of the foam
core and nonparallel to an adjoining surface of the shell. The
adjoining surface of the foam core may be the exposed surface of
the foam core of the mounting surface.
[0008] The shell of the architectural cast stone product may also
include one or more projections. A projection is a part of the
shell that extends into the foam core and may positively affix the
shell to the core. The projection may have any shape that assists
in affixing the shell to the core. It may be a simple bump
extending into the foam core. The projection may have a T or L
shape, with the top of the T being formed within the foam core and
the base of the T extending from a surface of the shell and the
base of the L being formed within the foam core and the top of the
L extending from a surface of the shell. It may be a geometric
shape, such as a rectangular shape, a trapezoid shape, a triangular
shape, a shape that follows an arc or other geometric shape.
[0009] The shell may be cast so that it has the appearance of a
miter joint. In other words, the shell may extend in a first
direction and a second direction with the second direction disposed
at an angle to the first direction. Where the first direction and
the second direction meet, a corner or miter joint is formed. The
foam core may be made of one piece or of multiple pieces, but the
shell is a solid cast unitary body.
[0010] The foam core may be made of any type of foamed polymer that
has sufficient strength to support the cast shell. Foam is any
material containing a distributed mass of gas bubbles. The foam
core may be made of a variety of foamed polymer materials
including, but not limited to, expanded polystyrene, polyurethane,
polyethylene, polypropylene, polyester, polyvinyl chloride,
polyacrylonitrile, ABS, polyamide, polyoxymethylene, polycarbonate,
rubber, phenolic, polyimide, acrylic, flouropolymer, epoxy, or
silicone polymers. The foamed polymer core should be capable of
being shaped in a three dimensional form through molding,
machining, extrusion, or any other generally known method in the
art.
[0011] Expanded polystyrene ("EPS") is an excellent foam core
material because of its ease of processing, relatively low density,
and relatively high strength. EPS is a generic term for polystyrene
and styrene copolymers that are shaped, expanded, and molded into
foam shapes. EPS may be purchased in large blocks having a density
from about 1 lbs/ft.sup.3 or greater. In some applications, a
density of about 1 lbs/ft.sup.3 to about 2.0 lbs/ft.sup.3 may be
preferred. In other applications, a density under 1 lbs/ft.sup.3
may be desired. EPS may also be easily shaped by a
computer-assisted foam-cutting machine that uses a hot wire to cut
the EPS block into the desired three dimensional shapes.
[0012] For example, a method for manufacturing an architectural
cast stone product for use in building construction may include the
steps of obtaining a front pattern having a desired surface
configuration for the architectural cast stone product, obtaining a
foam core, affixing the foam core to a backer, affixing the front
pattern to the backer, pouring a cementitious material into the
mold and into contact with the foam core, at least partially curing
the cementitious material to form the architectural cast stone
product, and removing the front pattern and backer from the
architectural cast stone product. The front pattern and the backer
together may form a mold. In some configurations, a cap may be used
to close one end of the mold.
[0013] Obtaining a front pattern may include cutting an EPS foam
block with a hot wire or computer-assisted foam-cutting machine
that has been pre-programmed with the desired shape of the front
pattern. The front pattern may also be obtained by thermoforming a
plastic sheet over a model or using standard machining practices to
obtain the desired shape of the front pattern. Alternatively, any
method known in the art for making a suitable mold may be used to
create the front pattern, such as molding, machining, or extrusion.
The front pattern is a first half of a mold in which the shell is
formed around the foam core. Of course, the front pattern may be
made from any metal, wood, plastic, ceramic, composite, or material
that is able to give the cementitious slurry a desired shape while
the cementitious slurry cures.
[0014] If an EPS foam block is cut, the foam core may be cut from
the same block as the front pattern during the same cutting
operation. The foam core may also be prepared by forming the core
material in a mold and allowing the foam core to cure.
Alternatively, standard machining practices or any other known
method may be used to prepare the foam core.
[0015] The front pattern is preferably shaped and disposed relative
to the foam core to create a cavity at least about 1/4 inch broad
between the front pattern and the foam core. In most applications,
the cavity ranges from about 1/4 inch to about 1 inch broad. In
some configurations, the cavity may be about 1/8 of an inch broad.
The breadth of the cavity determines the thickness of the
shell.
[0016] The foam core may include a three dimensional surface
configuration of the foam core similar to the surface of the front
pattern. When this is done, the shell of the architectural cast
stone product may have a substantially uniform thickness.
Controlling the shell thickness may allow a minimum amount of
cementitious material to be used, which further lightens the
architectural cast stone product and lowers manufacturing
costs.
[0017] The front pattern and the foam core may be attached to the
backer. The backer forms part of the mold in which the shell is
formed around the foam core. The backer helps to prevent the
cementitious slurry from flowing out of the mold and supports the
foam core. The backer also positions the foam core relative to the
front pattern so that shell is formed with a desired thickness. The
foam core is preferably affixed to the backer by mechanical
fasteners that include, but are not limited to, tape, cord, nails,
screws, nuts and bolts, straps, clamps, and various other types of
fasteners. The foam core may also be affixed to the backer by
adhesives including hot glue (polyethylene) or other types of
adhesives that do not dissolve the foam core.
[0018] The front pattern may be affixed to the backer by mechanical
fasteners that include, but are not limited to, tape, cord, nails,
screws, nuts and bolts, straps, clamps, and various other types of
fasteners. The front pattern is preferably affixed to the backer by
adhesives including hot glue (polyethylene) or other types of
adhesives that do not dissolve or damage the backer or the front
pattern. Alternatively, the front pattern may be affixed to the
backer by abutting other molds or heavy objects against the front
pattern and/or backer.
[0019] Before the backer and front pattern are affixed together,
the backer and front pattern may be covered with a mold release.
The mold release may include any known mold release known in the
art. For example, vegetable oil may be used as a mold release.
[0020] Once a mold is formed, a cementitious slurry is poured into
the mold. The mold may be vibrated while the cementitious material
is poured into the mold. Additionally, after the cementitious
material is poured into the mold, the mold may be vibrated. The
vibration helps remove air bubbles from the slurry of cementitious
material. Vibrating the mold to remove air bubbles from the
cementitious material usually increases the quality of the shell.
The cementitious material is then allowed to cure.
[0021] When the architectural cast stone product is partially cured
or after it is fully cured, the front pattern and the backer are
removed. Removal may be easier while the architectural cast stone
product is only partially cured. Once removed, the architectural
cast stone product may be sanded, polished, or undergo other
surface treatments to produce the desired surface finish. Of
course, the surface finish of the front pattern directly affects
the surface finish of the architectural cast stone product. For
instance, if denser EPS foam is used as a front pattern, then the
surface finish of the architectural cast stone product will be
smoother. Where the backer was affixed to the foam core, the foam
core will be exposed to view and will form part of the mounting
surface of the architectural cast stone product. However, the
mounting surface is preferably not seen once the architectural cast
stone product is mounted on a building structure. This partial
coverage of the foam core by the shell provides the benefit of
reducing the weight and expense of the architectural cast stone
product.
[0022] The cementitious material may be firmly attached to the foam
core in a number of ways. First, the foam used is not perfectly
smooth, so the cement slurry is able to fill the small crevices and
pores of the foam core. The three dimensional surface configuration
increases the surface area of the foam core for even greater
bonding. Additionally, a bonding agent may also be used to
encourage adhesion of the cementitious material to the foam core.
Wraparound extensions may also be formed that wrap around and
partially cover the exposed side of the foam core. The wraparound
extensions are formed when grooves are cut into the foam core, the
grooves are filled by the cementitious slurry, and the cementitious
slurry is allowed to cure forming the architectural cast stone
product. Protrusions of the shell may extend into the foam core,
which further increases the shell surface area for improved
bonding. The protrusions, like the wraparound extensions, help to
grip the foam core.
[0023] The mold may also include an affixed cap. The cap is used to
close an area of the mold that is not enclosed by the front pattern
or the backer. An area of the mold may be left open to provide a
conduit for the cementitious material to enter and fill the
mold.
[0024] To provide an architectural cast stone product with the
appearance of a miter joint a suitable mold must be obtained. This
may be accomplished by cutting a first mold and a foam core at a
desired angle. A second mold and a second foam core are also cut at
a desired angle. Then, the first mold and foam core are affixed to
second mold and the second foam core, respectively, to make a miter
mold. In this way, multiple molds may be combined to form a miter
mold to produce an architectural cast stone product with the
appearance of one or more miter joints.
[0025] A miter mold for casting an architectural cast stone product
with the appearance of a miter joint may also be produced by
machining, thermomolding, or molding the miter joint shape into the
front pattern directly, instead of combining two molds. In this
way, a single mold can be used to cast an architectural cast stone
product with the appearance of a miter joint. Additionally, the
foam core may be a unitary body and thus provide better support to
the shell as compared to multiple separate pieces of a foam core
that have been affixed to each other with adhesives or mechanical
fasteners.
[0026] Once the miter mold and foam core have been prepared, a
cementitious slurry is poured into a cavity of the miter mold
formed between the front pattern and the backer. The cementitious
slurry is then allowed to at least partially cure in the miter
mold. The resulting architectural cast stone product has the
appearance of a miter joint. This method produces an architectural
stone product that has a first part and a second part extending at
an angle from the first part so that where the first part meets the
second part, a miter joint or corner is formed.
[0027] An architectural cast stone product according to the
invention may have a shell with an average thickness that may be
greater than or equal to about 1/4 of an inch. The shell may also
have an average thickness from about 1/4 inch to about 1 inch or
greater. In other configurations the thickness of the shell may be
about 1/8 of an inch.
[0028] An architectural cast stone product prepared within the
scope of the invention limits waste of the cementitious stone base
material by using only the amount that is necessary to evenly cover
a foam core. In addition, an architectural cast stone product
requires minimal labor to prepare its mold, cast the architectural
cast stone product, and install the finished product on a building
structure. The architectural cast stone product according to the
invention may be made in any shape including, but not limited to,
linear, geometric, curved forms, and ornate three dimensional
shapes.
[0029] These and other features of the present invention will
become more fully apparent from the following description, or may
be learned by the practice of the invention as set forth
hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] In order that the manner in which the above-recited and
other features and advantages of the invention are obtained will be
readily understood, a more particular description of the invention
briefly described above will be rendered by reference to specific
embodiments thereof which are illustrated in the appended drawings.
Understanding that these drawings depict only typical embodiments
of the invention and are not therefore to be considered to be
limiting of its scope, the invention will be described and
explained with additional specificity and detail through the use of
the accompanying drawings, in which:
[0031] FIG. 1 is an exploded perspective view illustrating a front
pattern, backer, and cap of a mold and a foam core;
[0032] FIGS. 2a and 2b are perspective views illustrating the
assembly of the mold with a foam core;
[0033] FIG. 3 is a perspective view illustrating the assembled mold
and foam core;
[0034] FIG. 4 is a perspective view of a finished architectural
cast stone product removed from the mold;
[0035] FIG. 5a is an exploded view of a mold and a second mold,
each with a cut to create a miter mold;
[0036] FIG. 5b is a perspective view of an architectural cast stone
product having the appearance of a miter joint resulting from this
mitered mold;
[0037] FIG. 6 is a perspective view of an alternative configuration
of an architectural cast stone product;
[0038] FIG. 7 is a perspective view of a curved architectural cast
stone product that extends along an arc;
[0039] FIG. 8 is a perspective view of a half column; and
[0040] FIG. 9 is a perspective view of an alternative half of a
column within the scope of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0041] The presently preferred embodiments of the invention will be
best understood by reference to the drawings, wherein like parts
are designated by like numerals throughout. It will be readily
understood that the components of the present invention, as
generally described and illustrated in the figures herein, could be
arranged and designed in a wide variety of different
configurations. Thus, the following more detailed description of
the embodiments of the apparatus, system, and method of the present
invention, as represented in FIGS. 1 through 9 is not intended to
limit the scope of the invention, but is merely representative of
presently preferred embodiments of the invention.
[0042] For this application, the phrase "connected to" refers to
any form of interaction between two or more entities, including
mechanical, electrical, magnetic, electromagnetic, and thermal
interaction. The phrase "attached to" refers to a form of
mechanical coupling that restricts relative translation or rotation
between the attached objects. The terms "integrally formed" refer
to a body that is manufactured integrally, i.e., as a single piece,
without requiring the assembly of multiple pieces. Multiple parts
may be integrally formed with each other if they are formed from a
single work piece.
[0043] FIG. 1 is an exploded perspective view illustrating a mold
10. As shown, the mold 10 for producing an architectural cast stone
product comprises a front pattern 12, backer 14, and cap 16. A foam
core 18 is positioned within the mold 10. Each part in this
embodiment is composed of EPS, which is cut by a computer assisted
foam-cutting machine (not shown). Such foam-cutting machines use
one or more heated wires to quickly cut the foam. Of course, the
EPS may be manually cut using hot wires or other known cutting
methods.
[0044] In this embodiment, EPS is used because EPS is inexpensive,
commercially available, and easy to process. In addition, EPS that
has a density of about 1 lb/ft.sup.3 is sufficient to provide an
adequate surface finish on the exterior of the cast product. Of
course, higher density EPS foam, with densities in the range from
about 1.5 and 2 lb/ft.sup.3, may be used to provide a smoother
surface finish. Recycled EPS foam on the other hand tends to
provide a rough and inconsistent surface finish, but it may also be
used to make a foam core, front pattern, backer, cap, or any other
parts of a mold.
[0045] In addition to foam, the parts of the mold, including a
front pattern, backer, and optionally a cap, may be made of any
type of material including, but not limited to, metal, ceramic,
glass, composite, wood, or plastic. Of course, use of these other
materials may require different processing methods than what is
described in this embodiment. For example, a front pattern could be
cut in metal using electrical discharge machining ("EDM"), standard
machining processes, forging, or even casting. A plastic mold could
be thermoformed or machined.
[0046] The foam core 18 may be made of any foamed plastic. In this
embodiment, EPS is used because EPS is inexpensive and easy to form
in three dimensional shapes in order to make an architectural cast
stone product. For example, a foam core may be shaped by molding,
reaction injection molding, or standard machining methods. The foam
core 18 may also be cut by a computer-aided foam-cutting machine.
Often foam cutting machines use a hot wire to cut EPS foam. Linear
shapes are made by placing an EPS foam block on a computer-aided
foam-cutting machine, which controls the movement of a hot wire
through the EPS foam block. Corner pieces are made by mitering a
completed mold and attaching the mitered ends to produce a mold
with the desired corner angle. Curved shapes are produced by using
a preformed hot wire mounted on a pivot arm at the desired radius.
The preformed hot wire is then rotated through an EPS foam block to
cut the mold shape and foam core.
[0047] The front pattern 12 and the foam core 18 may be cut for
efficiency from the same large solid block of EPS. The foam core 18
includes one or more grooves 20 cut into the foam core 18 to shape
wraparound extensions of a shell formed from a cementitious
material. The wraparound extensions help to grip the foam core 18
and help affix the cementitious material to the foam core of the
architectural cast stone product. Also, the cap 16 may optionally
be integrally formed with either the front pattern 12 or the backer
14.
[0048] The exposed internal surfaces 22 of mold 10 may be coated
with a mold release for easier removal of the architectural cast
stone product. A variety of mold release materials known in the art
may be used, including but not limited to silicon, Teflon, oil, or
wax. For instance, cooking spray may be used as the mold release.
However, some mold release agents may dissolve or weaken the foam
mold and thus should be avoided.
[0049] In contrast, the foam core 18 is not coated with a mold
release because the foam core 18 preferably adheres to the
cementitious material. Typically, the cementitious slurry will
adhere to the foam core and be affixed to the foam core when fully
cured, so no bonding agents are necessary. Of course, all surfaces
to which the cementitious material is expected to adhere should be
clean and free of oil, grease, dirt, decomposed foam or anything
that might inhibit adhesion of the cementitious material to the
foam. However, the exposed external surface 26 of the foam core 18
may be coated with a bonding agent known in the art to promote
adhesion of a cementitious material to foam.
[0050] FIGS. 2a and 2b illustrate the assembly of the mold 10 with
a foam core 18 in two sub-views. As shown in FIG. 2a, the foam core
18 may be affixed to the backer 14 by an attachment joint 28
between the foam core 18 and the backer 14. The attachment joint 28
may use adhesives or mechanical fasteners to affix the foam core 18
and the backer 14. If an adhesive is used, the amount of adhesive
needs to be enough to affix the two parts together, but not so much
that it is difficult to separate the backer 14 from the foam core
18.
[0051] An attachment joint 30 may connect the pattern 12 to the
backer 14 by using an adhesive that may affix the front pattern 12
with the backer 14 by applying adhesive generously enough to
prevent the mold 10 from breaking while the cementitious material
is poured and cured. It will be appreciated that a lesser quantity
of adhesive may be used in attachment joint 30 if other means are
provided for affixing the front pattern 12 and backer 14 together.
Such affixing means may include, but are not limited to, tape,
clamps, screws, bolts, or even other molds positioned adjacent to
mold 10.
[0052] As shown in FIG. 2b, the attachment joint 32 of the cap 16
to the front pattern 12 and the backer 14 again uses a generous
amount of adhesive. The adhesive in attachment joints 28, 30, and
32 may comprise hot glue or other material capable of bonding the
foam mold 10 together and prevent the slurry from leaking out while
the cementitious material is poured and curing. In some cases,
tape, clamps, or fasteners may function as an adhesive.
[0053] If a corner or miter joint is needed, the mold 10 may be cut
to a desired angle. The mold 10 is then aligned with and affixed to
a second mold (not shown). For instance, if a right angle is
needed, both the mold 10 and the second mold may be cut at a 45
degree angle. The mold 10 and the second mold are then affixed in
order to provide a shell of an architectural cast stone product
with the appearance of a miter joint. Also shown in FIG. 2b is the
cavity 34 that is formed by the mold, which gives shape to poured
cementitious slurry.
[0054] FIG. 3 is a perspective view illustrating the assembled mold
10. As shown, the front pattern 12 is attached to the backer 14 and
the cap 16 via attachment joints 30 and 32, respectively. The foam
core 18 is attached to the backer 14 via attachment joint 28 and
the backer is securely attached to the cap 16 via attachment joint
32. The mold 10 as shown is ready to be filled with cementitious
slurry.
[0055] The cavity 34 is defined by a breadth 36, width 38, and a
length 40. In this embodiment, the breadth 36 is the shortest
distance across the cavity 34 between the front pattern 12 and the
foam core 18. The width 38 is a dimension that is perpendicular to
the breadth 36 of the cavity 34. Finally, the length 40 is a
dimension extending through the mold 10 and is perpendicular to
breadth 36 and width 38 in the mold 10 shown in FIG. 3.
[0056] Once the mold 10 is filly assembled, the cavity 34 is filled
with cementitious slurry that hardens and cures to form a
three-dimensional architectural cast stone product. The cavity 34
may have a breadth 36 in the range from about 1/4 inch to about 1
inch, which may result in an equivalent thickness of a shell of
cementitious material around the foam core 18. Of course, the
breadth 36 of the cavity 34 can be varied from about 1/8 of an inch
to beyond 1 inch to fit circumstances as needed. If the cavity 34
is broader, then the cementitious slurry may be thick or more
viscous and may contain various aggregate materials. If the cavity
34 is narrower, then the cementitious slurry may be thin or less
viscous.
[0057] While the slurry is being poured, the mold 10 may be
vibrated to help the cement slurry settle into the mold and help
rid the cementitious slurry of air bubbles. The mold 10 may also be
vibrated after the cementitious material is poured. The
cementitious material used in this embodiment may be a portland
cement, high aluminum cement, silicate cement, magnesium
oxychloride cement or any other material known in the art having
the qualities of cement. Polymeric binders and aggregates may be
used to simulate stone and function as a cementations material. A
presently preferred cementitions material is a limestone coating
material sold by ArcusStone Products, Inc., Oakland, Calif.
[0058] The mold 10 once filled is set aside to cure. Removal of the
architectural cast stone product from the mold 10 while the
architectural cast stone product is only partially cured may
facilitate removal of the front pattern 12. It has been found that
removal of a fully cured architectural stone structure may be more
difficult. Removal while partially cured may produce a cleaner
surface finish and may render the use of mold release agents
unnecessary.
[0059] FIG. 4 shows a perspective view of an architectural cast
stone product 42 removed from the mold 10 (not shown). The
architectural cast stone product 42 can be up to 8 feet in length
or longer if needed. Molds for longer architectural cast stone
products may be assembled by attaching additional molds and/or
sections to create a larger mold. Of course, smaller architectural
cast stone product of three feet or shorter in length may be easier
to manufacture, transport, and install.
[0060] As shown, the architectural cast stone product 42 includes a
unitary shell 44 and the foam core 18. The shell 44 is integrally
formed around the foam core 18. The shell 44 may comprise
wraparound extensions 46 to help affix the foam core 18 to the
shell 44. The wraparound extensions 46 also provide the
architectural cast stone product 42 with increased structural and
mechanical strength and stability without the need for the shell 44
to fully enclose the foam core 18.
[0061] The architectural cast stone product 42 also includes a
mounting surface 48. The mounting surface 48 has an exposed surface
50 of the foam core 18 and an exposed surface 52 of the shell 44.
In some configurations, the exposed surface 52 of the mounting
surface 48 is also a surface of the wraparound extension 46 of the
shell 44.
[0062] In this configuration, the wraparound extension 46 follows
the foam core 18 from a first surface 54 of the foam core 18 at
least partially onto the mounting surface 48. The wraparound
extension 46 of the shell 44 may also be described as extending
nonparallel to an adjoining surface 56 of the shell 44 and parallel
to an adjoining surface 58 of the foam core 18.
[0063] The unitary shell 44 of this embodiment may be generally
defined by three dimensions; thickness 60, length 62, and width 64.
The thickness 60 of the shell 44 may be greater than about 1/4 of
an inch. Typically, the thickness 60 of the shell 44 is from about
1/4 inch to about 1 inch. Of course, the thickness 60 of the shell
44 may vary through the width 64 and throughout the length 62.
[0064] FIG. 5a illustrates an exploded view of a mold 100 having a
foam core 102 with a second mold 104 having a second foam core 106.
The mold 100 and foam core are cut or formed at an angle to create
a miter 108. The mold 100 includes a front pattern 110 and a backer
112. In this embodiment, the front pattern 110 is affixed to the
backer 112 so that a cap (not shown) is not needed. The second mold
104 and second foam core 106 are similarly cut at an angle to form
a second miter 116. The second mold similarly includes a second
front pattern 118 and a second backer 120.
[0065] The front pattern 110 and the second front pattern 118
include a profile 121 and a second profile 122, respectively. The
profile 121 is defined by hidden lines in FIG. 5a. The front
pattern 110 extends around the profile 121 to close the mold 100
and leave only the miter 108 open when the front pattern 110 is
affixed to the backer 112. This may be accomplished by using a
separate cap or by having the cap structure integrally formed with
the front pattern 110 as shown. The profiles 121 and 122 give shape
to a shell of an architectural cast stone product produced in the
mold 100 and second mold 104.
[0066] Once cut, the miter 108 and the second miter 116 are affixed
together with an adhesive to create a miter joint between the mold
100 and the second mold 104 and the foam core 102 and the second
foam core 106. Of course, mechanical fasteners may also be used to
affix the miter 108 with the miter 116.
[0067] Once the mold 100 and the second mold 104 are assembled and
affixed together to form a miter mold 124, the miter mold 124 is
positioned so that cementitious material may be poured into and
fill the cavity of the miter mold 124. An opening for filling the
miter mold 124 is provided in the second mold 104. Once the miter
mold 124 is filled, the cementitious material is allowed to
partially or fully cure around the foam core 102 and the second
foam core 106. Thereafter, the front panel 110, second front panel
118, the backer 112, and the second backer 120 are removed. If
necessary, the resulting architectural cast stone product is
allowed to fully cure.
[0068] FIG. 5b illustrates an architectural cast stone product 126
removed from the miter mold 124 (shown in FIG. 5a). As shown, the
architectural cast stone product 126 includes a unitary shell 128
affixed to the foam core 102 and the second foam core 106. The
shell 128 has the appearance of a miter joint 130 and also includes
wraparounds 132. The shell 128 of this configuration has a
substantially uniform thickness 134, preferably greater than about
1/4 of an inch. The thickness 134 may range from about 1/4 inch to
about 1 inch or be as thin as about 1/8 of an inch. Greater
thickness are within the scope of the invention, but they are not
preferred.
[0069] FIG. 6, illustrates an alternative configuration of an
architectural cast stone product 150. The architectural cast stone
product 150 includes a shell 152 of cementitious material that
partially covers a foam core 154. The shell 152 includes
wraparounds 156 that extend parallel to an adjoining surface 158 of
the foam core 154 and nonparallel to an adjoining surface 160 of
the shell 152. The wraparounds 156 extend opposite a surface 162 of
the shell 152 with a portion of the foam core 154 in between. The
positioning of the wraparounds 156 allows the shell 152 to grip the
foam core 154 with a minimum amount of material. This architectural
cast stone product 150 may be used as crown molding, where its
light weight is an advantage over solid cut or cast stone
products.
[0070] As crown molding, architectural cast stone product 150 has a
large mounting surface 163 that covers two sides of the
architectural cast stone product 150. The mounting surface 163
allows the architectural cast stone product 150 to be mounted into
the corner 164 formed where a surface of a ceiling 166 meets a
surface of a wall 168 of a structure 170. The architectural cast
stone product 150 may be attached to the surfaces of the ceiling
166 and the wall 168 of the structure 170 by mechanical fasteners
and/or adhesives.
[0071] The wraparounds 156 are formed and seated in grooves 172.
The wraparounds 156 provide an exposed surface 174 of the shell 152
that is part of the mounting surface 163. The exposed surface 176
of the foam core 154 is another part of the mounting surface 163.
When attached to the structure 170, the mounting surface 163 is not
open to view. Only the shell 152 remains exposed to view and
provides the appearance of a cut or carved stone crown molding.
[0072] FIG. 7, illustrates another configuration of an
architectural cast stone product 180 that extends along a curve
182. The architectural cast stone product 180 includes a shell 184
that partially covers a foam core 186. This architectural cast
stone product 180 may be used as a window surround or a door
surround. This configuration also includes wraparounds 188.
[0073] The foam core 186 and mold (not shown) may be cut by moving
a shaped hot wire (not shown) through an arc or curve to cut a foam
block. Of course, the foam core 186 may also be molded or machined.
Therefore, the architectural cast stone product within the scope of
the present invention may have many different shapes.
[0074] FIG. 8 illustrates an alternative configuration of another
cast stone product 200 within the scope of the invention. The
architectural cast stone product 200 is shaped as half of a
cylindrical column. The architectural cast stone product 200
includes a shell 202 partially surrounding a foam core 204. The
architectural cast stone product 200 also includes a mounting
surface 206.
[0075] The shell 202 extends over a 180 degree arc and includes
projections 208 that extend into the foam core 204. The projections
208 help affix the shell 202 to the foam core 204.
[0076] The mounting surface 206 includes a channel 210 that allows
the architectural cast stone product 200 to fit around a structural
element, such as a beam, of a building. The mounting surface 206
also includes assembly features 212 that allow the architectural
cast stone product 200 to be properly aligned and securely attached
to a complimentary architectural cast stone product (not shown).
Assembly features 212 may be configured to allow the architectural
cast stone product 200 to be properly spaced relative to a
structural support or the complimentary architectural cast stone
product (not shown). As shown, the assembly features 212 may have
an extension 214 and a groove 216 that would engage reciprocal
features of a similar architectural cast stone product.
[0077] FIG. 9 illustrates yet another alternative architectural
cast stone product 230. The architectural cast stone product 230 is
shaped as half of a square, fluted column. The architectural cast
stone product 230 includes a shell 232 partially surrounding a foam
core 234. Similar to FIG. 8, the architectural cast stone product
230 includes a mounting surface 236 having a channel 238 and
assembly features 240 that include an extension 242 and groove
244.
[0078] In contrast to the architectural cast stone product 200 of
FIG. 8, the architectural cast stone product 230 includes large
flutes 246 that help affix the shell 232 to the foam core 234. The
flutes 246 extend into the foam core 234 and are nonparallel to an
adjacent surface 248 of the shell 232. The flutes 246 are a type of
projection and allow the architectural cast stone product 230 to
avoid the use of wraparound extensions.
[0079] The architectural cast stone product 230, when combined with
one or more complimentary architectural cast stone products (not
shown), provides a light-weight, aesthetically-pleasing column for
use in building structures or landscaping as a freestanding
column.
[0080] The use of a shell of cementitious material covering a foam
core provides the pleasing appearance of solid cast stone or
natural stone architectural products. The light weight of
architectural cast stone products within the scope of the invention
facilitates installation and positioning on building structures.
The minimal use of cementitious material in the architectural cast
stone products also significantly lessens the costs of using
architectural stone products in building structures for aesthetic
or structural purposes.
[0081] The method of producing architectural cast stone products
within the scope of the invention also provides architectural cast
stone products with consistent qualities such as thickness of the
shell and uniformity of appearance. The method of producing
architectural cast stone products also provides for the production
of standard, interchangeable, as well as custom architectural cast
stone products.
[0082] The present invention may be embodied in other specific
forms without departing from the structures, methods, or other
essential characteristics as broadly described herein and claimed
hereinafter. The described embodiments are to be considered in all
respects only as illustrative, and not restrictive. The scope of
the invention is, therefore, indicated by the appended claims,
rather than by the foregoing description. All changes that come
within the meaning and range of equivalency of the claims are to be
embraced within their scope.
* * * * *